Mechanical properties of Michigan Basin’s gypsum before and after saturation  

作　　者：Mohammadhossein Sadeghiamirshahidi Stanley J.Vitton 

机构地区：[1]Department of Civil and Environmental Engineering, Michigan Technological University

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2019年第4期739-748,共10页岩石力学与岩土工程学报（英文版）

摘　　要：The stability analysis of an abandoned underground gypsum mine requires the determination of the mine pillar’s strength.This is especially important for flooded abandoned mines where the gypsum pillars become saturated and are subjected to dissolution after flooding.Further,mine pillars are subjected to blast vibrations that generate some level of macro- and micro-fracturing.Testing samples of gypsum must,therefore,simulate these conditions as close as possible.In this research,the strength of gypsum is investigated in an as-received saturated condition using uniaxial compressive strength (UCS),Brazilian tensile strength (BTS) and point load index (PLI) tests.The scale effect was investigated and new correlations were derived to describe the effect of sample size on both UCS and BTS under dry and saturated conditions.Effects of blasting on these parameters were observed and the importance of choosing the proper samples was discussed.Finally,correlations were derived for both compressive and tensile strengths under dry and saturated conditions from the PLI test results,which are commonly used as a simple substitute for the indirect determination of UCS and BTS.The stability analysis of an abandoned underground gypsum mine requires the determination of the mine pillar’s strength.This is especially important for flooded abandoned mines where the gypsum pillars become saturated and are subjected to dissolution after flooding.Further,mine pillars are subjected to blast vibrations that generate some level of macro-and micro-fracturing.Testing samples of gypsum must,therefore,simulate these conditions as close as possible.In this research,the strength of gypsum is investigated in an as-received saturated condition using uniaxial compressive strength(UCS),Brazilian tensile strength(BTS)and point load index(PLI)tests.The scale effect was investigated and new correlations were derived to describe the effect of sample size on both UCS and BTS under dry and saturated conditions.Effects of blasting on these parameters were observed and the importance of choosing the proper samples was discussed.Finally,correlations were derived for both compressive and tensile strengths under dry and saturated conditions from the PLI test results,which are commonly used as a simple substitute for the indirect determination of UCS and BTS.

关 键 词：UNIAXIAL compressive STRENGTH (UCS) Brazilian tensile STRENGTH (BTS) Point load index (PLI) Scale effect MICHIGAN Basin's GYPSUM 

分 类 号：TD311[矿业工程—矿井建设]